// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#ifndef CEPH_OSDC_WRITEBACKHANDLER_H
#define CEPH_OSDC_WRITEBACKHANDLER_H

#include "include/Context.h"
#include "include/types.h"
#include "common/zipkin_trace.h"
#include "osd/osd_types.h"

class WritebackHandler {
public:
    WritebackHandler() {}
    virtual ~WritebackHandler() {}

    virtual void read(const object_t& oid, uint64_t object_no,
        const object_locator_t& oloc, uint64_t off, uint64_t len,
        snapid_t snapid, ceph::buffer::list* pbl, uint64_t trunc_size,
        __u32 trunc_seq, int op_flags,
        const ZTracer::Trace& parent_trace, Context* onfinish) = 0;
    /**
     * check if a given extent read result may change due to a write
     *
     * Check if the content we see at the given read offset may change
     * due to a write to this object.
     *
     * @param oid object
     * @param read_off read offset
     * @param read_len read length
     * @param snapid read snapid
     */
    virtual bool may_copy_on_write(const object_t& oid, uint64_t read_off,
        uint64_t read_len, snapid_t snapid) = 0;
    virtual ceph_tid_t write(const object_t& oid, const object_locator_t& oloc,
        uint64_t off, uint64_t len,
        const SnapContext& snapc,
        const ceph::buffer::list& bl, ceph::real_time mtime,
        uint64_t trunc_size, __u32 trunc_seq,
        ceph_tid_t journal_tid,
        const ZTracer::Trace& parent_trace,
        Context* oncommit) = 0;

    virtual void overwrite_extent(const object_t& oid, uint64_t off, uint64_t len,
        ceph_tid_t original_journal_tid,
        ceph_tid_t new_journal_tid) {}

    virtual bool can_scattered_write() { return false; }
    virtual ceph_tid_t write(const object_t& oid, const object_locator_t& oloc,
        std::vector<std::pair<uint64_t, ceph::buffer::list> >& io_vec,
        const SnapContext& snapc, ceph::real_time mtime,
        uint64_t trunc_size, __u32 trunc_seq,
        Context* oncommit) {
        return 0;
    }
};

#endif
